1. Field of the Invention
The present invention relates to a method for examining a specimen in a particle beam instrument, whereby the specimen is irradiated with a particle probe and secondary particles triggered by the particle probe are documented.
2. Description of the Prior Art
There is an increasing need for imaging methods in all areas of development and manufacture of micro-electronic and opto-electronic components in order to be able to visually evaluate micrometer structures, to identify deviations from rated patterns and to localize the defects produced on masks and wafers by particle occupation. Due to the low depth of field, light-optical methods can only be utilized within limits for defect recognition in submicrometer structures. Electron-optical imaging methods were therefore developed wherein the subject to be examined is scanned with a focused electron beam and the current of secondary electrons modulated by topography, material or voltage contrast is registered in a detector. Since the signal-to-noise ratio need for a reliable defect recognition limits the scan rate, these methods allow only a low throughput of inspected subjects.